Fix deletion of export locations
Fix deletion of export locations

Export locations stored in separate table are not deleted. Never.
Fix it for two cases: when share deletion is performed and export locations
update operation that 'share driver's do.

Change-Id: I7b66c8843647862e398e71898ac258f07f264e3a
Closes-Bug: #1435313

bswartz/manila,redhat-openstack/manila,vponomaryov/manila,openstack/manila,jcsp/manila,scality/manila,weiting-chen/manila,vponomaryov/manila,openstack/manila,weiting-chen/manila,bswartz/manila,redhat-openstack/manila,sajuptpm/manila,NetApp/manila,sajuptpm/manila,jcsp/manila,NetApp/manila,scality/manila